Heat exchanger and method for producing a heat exchanger

ABSTRACT

The invention relates to a heat exchanger for a motor vehicle, comprising a heat exchanger block and at least one collection box with a tube plate. The heat exchanger block is made of a plurality of adjacent tubes and corrugated rib elements arranged between the tubes, and one of the end regions of the tubes is received in the tube plate of the collection box in a fluid-tight manner. The tube plate of the collection box is made of plastic and is injection molded onto the heat exchanger block. A spacer element through which the tubes are guided is arranged between the tube plate of the collection box and the heat exchanger block, and the corrugated rib elements are spaced from the tube plate of the collection box by the spacer. The invention further relates to a method for producing a heat exchanger.

TECHNICAL FIELD

The invention relates to a heat exchanger for a motor vehicle, comprising a heat exchanger block and at least one collection box with a tube plate, wherein the heat exchanger block is made of a plurality of tubes adjacent to one another and corrugated fin elements arranged therebetween, and one of the end regions of the tubes is received in the tube plate of the collection box in a fluid-tight manner. Moreover, the invention relates to a method for producing a heat exchanger.

STATE OF THE ART

Heat exchangers by means of which a heat transfer is produced between a first fluid and a second fluid are used for cooling or heating fluids in motor vehicles.

A wide variety of heat exchanger designs is known in the art. Known designs also include, among other things, heat exchangers which exhibit a so-called tube/fin construction. In designs of this kind when there is a plurality of tubes, the tube ends are received in openings in a tube plate at the end, said tube plate in turn being connected to a cover-like element to form a collection box. Corrugated fin elements may be arranged between the tubes, said elements promoting the heat transfer between a fluid flowing in the tubes and a fluid flowing around the tubes.

The tubes, the corrugated fin elements and the tube plates are produced from a metallic material in some embodiments known in the art. The cover-like elements in this case are either made from a metallic material, such as aluminum, or from a plastic.

The disadvantage of the heat exchangers known in the art is, in particular, that due to the large range of variants, tubes with different geometries are used, the tubes are arranged at different distances from one another and the number of tubes used also varies. It is therefore only possible with some difficulty for modular components to be used for the production of heat exchangers, which means that the production of heat exchangers is time-consuming and expensive.

In the state of the art, heat exchangers are furthermore known which have a collection box made of plastic which is injection-molded straight onto the tubes and corrugated fin elements.

A disadvantage of the heat exchangers known in the art with a collection box injection molded onto them is, in particular, that the heat exchanger block formed from tubes and corrugated fin elements is not sufficiently protected against contact with plastic during the injection process. The sensitive corrugated rib elements are also not adequately protected against the pressures occurring during the injection process, which means that damage can occur, particularly to the corrugated fin elements. The heat exchangers with a collection box injection-molded onto them therefore often have only a very small number of tubes, as a result of which the performance of the heat exchanger is greatly limited.

Representation of the Invention, Problem, Solution, Advantages

The problem addressed by the present invention is therefore that of creating a heat exchanger which is an improvement on the state of the art and exhibits means which protect the heat exchanger block formed from tubes and corrugated fin elements during the injection process from plastic and the resulting working pressure. Moreover, the problem addressed is that of creating a method of producing a heat exchanger.

The problem in relation to the heat exchanger is solved by a heat exchanger having the features of claim 1.

An exemplary embodiment of the invention relates to a heat exchanger for a motor vehicle, having a heat exchanger block and having at least one collection box with a tube plate, wherein the heat exchanger block comprises a plurality of tubes arranged adjacent to one another and corrugated fin elements arranged therebetween, and the end regions of the tubes are received in the tube plate of the collection box in a fluid-tight manner, wherein the tube plate of the collection box is made of plastic and is molded onto the heat exchanger block by injection molding, wherein a spacer element is arranged between the collection box and the heat exchanger block, through which the tubes are conducted, wherein the corrugated fin elements are spaced apart from the tube plate of the collection box by the spacer element.

The tubes and the corrugated fin elements are made of a metallic material and are connected to one another by a soldering method or a welding method. Alternatively, the tubes and corrugated fin elements may also be held by means of a tool device, until an adequate connection is produced between the elements by injection-molding the tube plate of the collection box.

The heat exchanger may only exhibit a collection box or, in an alternative exemplary embodiment, also two collection boxes. In only one collection box, the tubes may either be received therein at the ends, while the other end region in each case is received in another structure, or the tubes may be of U-shaped configuration, for example, so that the tubes are each received with both end regions in the on collection box.

The tube plate of the collection box is advantageously made of plastic and molded onto the heat exchanger block by injection molding. This is particularly advantageous, since the tube plate of the collection box can be produced quickly and easily and can be adapted to different heat exchangers particularly easily. For this purpose, only the mold need be adapted for the production of the injection-molded tube plate of the collection box. The tube plate of the collection box or else of the collection box or the heat exchanger can therefore easily be produced in a wide variety of variants.

It is particularly preferable for a spacer element to be arranged between the heat exchanger block and the tube plate of the collection box. This primarily performs a separating function and a protective function. The spacer element advantageously prevents the plastic of the tube plate of the collection box from penetrating between the corrugated fin elements and damaging them. Moreover, the heat exchanger block is protected by the spacer element from the high pressures that occur during the injection-molding of the plastic and, in particular, can damage the partially thin-walled tubes and likewise very thin-walled corrugated fin elements.

It is also advantageous for the spacer element to be formed by a perforated plate exhibiting openings that match the tubes in the heat exchanger block in such a manner that they project through the openings with an accurate fit.

A configuration of the spacer element as a perforated plate is particularly advantageous, as in this way the end regions of the tubes can be guided through the spacer element, on the one hand, while the corrugated fin elements are otherwise covered by the spacer element. In this way, the collection box can easily be injection-molded onto the heat exchanger block, without the corrugated fin elements being damaged in the process.

The openings in the spacer element are preferably configured with only a small amount of play in respect of the tubes, so as to allow the best possible fit of the tubes in the spacer element. This is particularly advantageous in preventing plastic from penetrating through between the tubes and the openings during the injection-molding of the tube plate of the collection box and thereby damaging the corrugated fin elements.

It is also preferable for the tube plate of the collection box to be injection-molded onto the heat exchanger block using a plastic injection-molding process. A plastic injection-molding process is particularly advantageous for production of the tube plate of the collection box, as on the one hand it allows high dimensional freedom and, on the other hand, the production of a collection box with an adequately great pressure resistance is made possible.

Moreover, it is advantageous for the tubes to have at the end an at least partially circumferential groove and/or to be roughened at the end.

An at least partially circumferential groove and/or a surface-pretreated and/or coated, also roughened, for example, end region are advantageous in producing a better connection between the tubes and the injection-molded tube plate of the collection box. The groove may form an edge which is engaged behind by a partial region of the tube plate of the collection box, as a result of which the connection is improved. Roughness in the region of the tube end may improve the toothing between the plastic of the tube plate of the collection box and the tubes.

Furthermore, it is advantageous for the heat exchanger to exhibit two collection boxes, wherein the tubes each open out at the ends into one of the collection boxes and are connected in a fluid-tight manner thereto, wherein a spacer element is arranged between each of the collection boxes and the heat exchanger block.

Particularly advantageous is a heat exchanger with two collection boxes opposite one another, which are connected to one another fluidically by the tubes of the heat-exchanger block. The heat exchanger can thereby be flowed through conventionally from a collection box through the tubes to the opposite connection box. Depending on the embodiment of the collection boxes, a single or multiple deflection of the fluid flowing through the heat exchanger may also be achieved in this way, as a result of which different through-flow principles can be achieved. The different through-flow principles in this case substantially correspond to the through-flow principles of conventional heat exchangers.

It is also advantageous for the spacer element to be coated with plastic on the side turned away from the heat exchanger block, which forms the tube plate of the collection box, wherein the tubes are connected to the injection-molded tube plate of the collection box in a substance-bonded and/or positive-locking manner.

It is particularly advantageous for the collection box to be limited on all sides by the injection-molded plastic. This is particularly advantageous if the spacer element is not connected to the tubes in a fluid-tight manner. This means that the spacer element forms a surface onto which the tube plate of the collection box is injection-molded. However, the tube plate of the collection box in this case is preferably connected to the tube sections protruding through the spacer element, as a result of which the tube plate of the collection box is directly attached to the heat exchanger block and the tubes are connected to the tube plate of the collection box in a fluid-tight manner. Depending on the embodiment of the tubes and/or the tube plate of the collection box, a substance-bonded and/or positive-locking connection may be produced in this case between the tubes and the tube plate of the collection box.

Moreover, it is advantageous for the spacer element to form a reinforcement of the plate region of the collection box facing the heat exchanger block, wherein the spacer element is connected to the collection box in a positive-locking and/or substance-bonded manner.

In an advantageous embodiment, the spacer element which may be formed from a metallic material, for example, may form a reinforcement of the plate region of the collection box facing the heat exchanger block. This increases the stability of the collection box and therefore also the durability of the heat exchanger. The spacer element may, for example, exhibit ledges, edges or roughened regions for this purpose, which improve the connection between the plastic of the collection box and the spacer element.

Furthermore, it is advantageous for the spacer element to be soldered and/or welded and/or clamped and/or adhered to the tubes and/or the corrugated fin elements. Depending on the choice of material for the spacer element, this may be connected to the tubes and/or the corrugated fin elements, as a result of which the strength of the heat exchanger can be increased.

The problem in respect of the method is solved by a method having the features of claim 9.

An exemplary embodiment of the invention relates to the method of producing a heat exchanger, wherein a heat exchanger block is produced from a plurality of tubes adjacent to one another and corrugated fin elements arranged therebetween, wherein a spacer element is placed on the tubes at the ends and the tube plate of the collection box is injection-molded integrally to the heat exchanger block and/or the spacer element.

The heat exchanger block can preferably be produced in a conventional manner, in that the tubes are soldered to the corrugated fin elements, for example. An independent component is thereby produced which can be selectively further processed. The addition of the spacer element is advantageous in preventing damage to the corrugated fin elements by plastic parts during the subsequent injection-molding of the tube plate of the collection box. The tube plate of the collection box is advantageously injection-molded onto the heat exchanger block in such a way that a fluid-tight and pressure-tight connection is produced between the tube ends projecting through the spacer element and the inside of the injection-molded tube plate of the collection box.

It is also advantageous for the tubes to penetrate the spacer element through precise openings formed in it and the corrugated fin elements are completely covered by the spacer element. This is particularly advantageous in achieving a play-free fit of the spacer element on the heat exchanger block wherever possible and to avoid the injection of plastic into the region filled by the corrugated fin elements.

Furthermore, it is preferable for the tube plate of the collection box to be injection-molded to the tubes projecting through the spacer element, wherein the tube plate of the collection box is connected to the projecting sections of the tubes and/or the spacer element in a substance-bonded and/or positive-locking manner.

This is particularly advantageous, since a fluid-tight and pressure-tight connection must be produced between the tubes and the tube plate, in order to guarantee the functionality of the heat exchanger. The corrugated fin elements are regularly embodied in a very delicate manner, which means that they are particularly prone to mechanical deterioration. The connection of the tube plate of the collection box to the heat exchanger block should therefore preferably not be produced via the corrugated fin elements.

The collection box is formed or sealed by connecting a tube plate of the collection box to a cover of the collection box. In this case, the tube plate and the cover can be produced separately and connected to one another or they may be jointly produced by injection-molding.

Advantageous developments of the present invention are described in the dependent claims and in the following figure description.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, the invention is explained in detail with the help of exemplary embodiments with reference to the drawings. In the drawings:

FIG. 1 shows a sectional view through an end region of a heat exchanger block, wherein the tubes open out into a tube plate of the collection box injection-molded onto the heat exchanger block and a spacer element is arranged between the tube plate of the collection box and the corrugated fin elements, and

FIG. 2 shows a plan view of a spacer element, as was used in FIG. 1 for the spacing of the tube plate of the collection box from the corrugated fin elements.

PREFERRED EMBODIMENT OF THE INVENTION

FIG. 1 shows a sectional view through a heat exchanger 1. The heat exchanger 1 has a heat exchanger block 7, which is formed by a plurality of tubes 2 and corrugated fin elements 3 arranged therebetween. The heat exchanger block 7 is conventional in design, the tubes 2 being arranged parallel to one another and spaced apart from one another. In the gaps between the tubes 2, corrugated rib elements 3 are arranged and are in thermally conductive contact with the tubes 2.

The tubes 2 exhibit a longer extension than the corrugated fin elements 3, which is why the corrugated fin elements 3 project laterally from the heat exchanger block 7. A spacer element 4 is placed on the projecting tubes 2, which spacer element exhibits a plurality of openings 6. The tubes 2 project through the openings 6. The cross sections of the openings 6 are adapted to the cross sections of the tubes 2, as a result of which a play-free fit of the spacer element 4 on the tubes 2 is achieved. The spacer element 4 or else the openings 6 is/are adapted to the arrangement of the tubes 2 within the heat transmission block 7.

A collection box 5 with a tube plate 8 is attached to the spacer element 4, which is produced by an injection method. The tube plate 8 of the collection box 5 is injection-molded straight onto the heat exchanger block 7. The tube plate 8 of the collection box 5 is injection-molded around the sections of the tubes 2 projecting through the spacer element 4, as a result of which, depending on the configuration of the tubes 2, a positive-locking and/or substance-bonded connection is produced.

The spacer element 4 may likewise be spray-coated completely or partially with the plastic of the tube plate 8 of the collection box 5, as a result of which a positive-locking and/or substance-bonded connection is likewise produced. The spacer element 4 may either be fitted onto the tubes 2 of the heat exchanger block or connected to the tubes 2 and/or the corrugated fin elements 3. This may be achieved by, among other things, conventional joining techniques, such as welding or soldering.

The main purpose of the spacer element 4 is to prevent plastic from penetrating the region of the corrugated fin elements 3 during the injection-molding process, in which the collection box 5 or the tube plate 8 of the collection box 5 is configured, and causing damage to or obstruction of the corrugated fin elements 3 there. In this case, with a separate configuration of the tube plate 8, said tube plate can be joined to a cover to form the collection box 5.

The collection box 5 is depicted is a box-shaped body in FIG. 1 which receives the regions at the ends of the tubes 2 of the heat exchanger block 7. In alternative exemplary embodiments, the tube plate 8 of the collection box 5 and also the collection box 5 may also assume different shapes. In particular, the shape of the tube plate 8 and of the collection box 5 must be adapted to the planned application. The collection box 5 may be formed by a single section on the inside or be divided into several sections by partition walls which are co-produced during the injection-molding process.

A change in the shape of the collection box 5 and/or of the tube plate 8 may be achieved by simply influencing the tool used for injecting the plastic. By using a suitable tool and the spacer element 4, a functional heat exchanger 1 can be produced which, in particular, can be produced without damage to the heat exchanger block 7, putting the available installation space to the best possible use. Furthermore, time-consuming sealing work and additional sealing elements are not necessary, as the tube plate 8 of the collection box 5 is integrally formed. Through the use of suitable plastics, adequate and satisfactory durability can be achieved.

FIG. 2 shows a plan view of a spacer element 4. The spacer element 4 has a rectangular, plate-shaped form. Along the spacer element 4 are arranged several openings 6 which are used to guide through the end regions of the tubes 2. The openings 6 are, as already mentioned, adapted to the arrangement of the tubes 2 and have a cross section that corresponds to the outer diameter of the tubes 2 in such a manner that the smallest possible play is produced between the spacer element 4 and the tubes 2.

In FIG. 2, the corrugated fins 3 arranged behind the spacer element 4 are indicated by dotted lines 3. The spacer element 4 may be formed from the same material as the tubes 2 and the corrugated fins 3 or likewise from a plastic, like the tube plate 8 of the collection box 5, for example.

The exemplary embodiments in FIGS. 1 and 2 are exemplary and explain the basic idea underlying the invention. They do not exhibit a limiting character, particularly with regard to the shape, material choice and embodiment of the individual elements. The heat exchanger block 7, in particular, may be configured in a variety of ways deviating from the exemplary embodiment shown in FIG. 1, in that the tubes and/or the corrugated fins are differently configured and the arrangement differs relative to one another. 

1. A heat exchanger for a motor vehicle, comprising a heat exchanger block and at least one collection box, wherein the heat exchanger block is made of a plurality of tubes adjacent to one another and corrugated fin elements arranged therebetween, and one of the end regions of the tubes is received in the tube plate of the collection box in a fluid-tight manner, wherein the tube plate of the collection box is made of plastic and is molded onto the heat exchanger block by injection molding, wherein a spacer element is arranged between the tube plate of the collection box and the heat exchanger block, through which the tubes are conducted, wherein the corrugated fin elements are spaced apart from the tube plate of the collection box by the spacer element.
 2. The heat exchanger as claimed in claim 1, wherein the tube plate of the collection box is connected to a cover of the collection box to form the collection box.
 3. The heat exchanger as claimed in claim 1, wherein the spacer element is formed by a perforated plate exhibiting openings that match the tubes in the heat exchanger block in such a manner that they project through the openings with an accurate fit.
 4. The heat exchanger as claimed in claim 1, wherein the tube plate of the collection box is injection-molded onto the heat exchanger block using a plastic injection-molding process.
 5. The heat exchanger as claimed in claim 1, wherein the tubes have at the end an at least partially circumferential groove and/or are surface-treated and/or coated at the end.
 6. The heat exchanger as claimed in claim 1, wherein the heat exchanger has two collection boxes, wherein the tubes each open out at the ends into one of the collection boxes and are connected in a fluid-tight manner thereto, wherein a spacer element is arranged between each of the collection boxes and the heat exchanger block.
 7. The heat exchanger as claimed in claim 1, wherein the spacer element is coated with plastic on the side turned away from the heat exchanger block, which forms the tube plate of the collection box, wherein the tubes are connected to the injection-molded tube plate of the collection box in a substance-bonded and/or positive-locking manner.
 8. The heat exchanger as claimed in claim 1, wherein the spacer element forms a reinforcement of the plate region of the collection box facing the heat exchanger block, wherein the spacer element is connected to the tube plate of the collection box in a positive-locking and/or substance-bonded manner.
 9. The heat exchanger as claimed in claim 1, wherein the spacer element is soldered and/or welded and/or clamped and/or adhered to the tubes and/or the corrugated fin elements.
 10. A method for producing a heat exchanger as claimed in claim 1, wherein a heat exchanger block is produced from a plurality of tubes adjacent to one another and corrugated fin elements arranged therebetween, wherein a spacer element is placed on the tubes at the ends and the tube plate of the collection box is injection-molded integrally to the heat exchanger block and/or the spacer element.
 11. The method for producing a heat exchanger as claimed in claim 10, wherein the tubes penetrate the spacer element through precise openings formed in it and the corrugated fin elements are completely covered by the spacer element.
 12. The method as claimed in claim 10, wherein the tube plate of the collection box is injection-molded onto the tubes projecting through the spacer element, wherein the tube plate is connected to the projecting sections of the tubes and/or the spacer element in a substance-bonded and/or positive-locking manner. 